[PATCH] uml: return hotplug errors to host

I noticed that errors happening while hotplugging devices from the host were
never returned back to the mconsole client.  In some cases, success was
returned instead of even an information-free error.

This patch cleans that up by having the low-level configuration code pass back
an error string along with an error code.  At the top level, which knows
whether it is early boot time or responding to an mconsole request, the string
is printk'd or returned to the mconsole client.

There are also whitespace and trivial code cleanups in the surrounding code.

Signed-off-by: Jeff Dike <jdike@addtoit.com>
Cc: Paolo 'Blaisorblade' Giarrusso <blaisorblade@yahoo.it>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

1 files changed, 15 insertions, 7 deletions

diff --git a/arch/um/drivers/stdio_console.c b/arch/um/drivers/stdio_console.c
index 9b2dd0b..3cbfe3a 100644
--- a/arch/um/drivers/stdio_console.c
+++ b/arch/um/drivers/stdio_console.c
@@ -52,9 +52,9 @@ static struct chan_opts opts = {
 	.in_kernel 	= 1,
 };
 
-static int con_config(char *str);
+static int con_config(char *str, char **error_out);
 static int con_get_config(char *dev, char *str, int size, char **error_out);
-static int con_remove(int n);
+static int con_remove(int n, char **con_remove);
 
 static struct line_driver driver = {
 	.name 			= "UML console",
@@ -87,9 +87,9 @@ static struct line vts[MAX_TTYS] = { LINE_INIT(CONFIG_CON_ZERO_CHAN, &driver),
 				     [ 1 ... MAX_TTYS - 1 ] =
 				     LINE_INIT(CONFIG_CON_CHAN, &driver) };
 
-static int con_config(char *str)
+static int con_config(char *str, char **error_out)
 {
-	return line_config(vts, ARRAY_SIZE(vts), str, &opts);
+	return line_config(vts, ARRAY_SIZE(vts), str, &opts, error_out);
 }
 
 static int con_get_config(char *dev, char *str, int size, char **error_out)
@@ -97,9 +97,9 @@ static int con_get_config(char *dev, char *str, int size, char **error_out)
 	return line_get_config(dev, vts, ARRAY_SIZE(vts), str, size, error_out);
 }
 
-static int con_remove(int n)
+static int con_remove(int n, char **error_out)
 {
-	return line_remove(vts, ARRAY_SIZE(vts), n);
+	return line_remove(vts, ARRAY_SIZE(vts), n, error_out);
 }
 
 static int con_open(struct tty_struct *tty, struct file *filp)
@@ -192,7 +192,15 @@ __uml_exitcall(console_exit);
 
 static int console_chan_setup(char *str)
 {
-	return line_setup(vts, ARRAY_SIZE(vts), str);
+	char *error;
+	int ret;
+
+	ret = line_setup(vts, ARRAY_SIZE(vts), str, &error);
+	if(ret < 0)
+		printk(KERN_ERR "Failed to set up console with "
+		       "configuration string \"%s\" : %s\n", str, error);
+
+	return 1;
 }
 __setup("con", console_chan_setup);
 __channel_help(console_chan_setup, "con");